930 transaxle stuck in third after adjustment attempt
 

Recently worked to tweak shifting performance of my 1982 Porsche 930 with four speed transaxle, the motor is a 930/60, believe the trainable is the shorter version. She was shifting great but felt I could adjust shifter coupling to improve it a bit (famous last words). While working different settings I somehow ended up with the transmission shaft refusing to rotate and the transaxle locked in third. The shaft moves forward and back ok but won't rotate. I had removed the coupling to examine it, the locking screw hole is somewhat stripped (soft aluminum), perhaps the shaft went back into the transaxle too far and fell off a fork or something? Clearly I have no clear idea of what goes on inside with the shaft but it won't rotate so third it is. Any help would be appreciated.

Sounds like you need a new coupler. The Wevo is best and the origonal has slop built into the bushings unless you make your own and install them.

If you have the origonal shift rod, the bottom half before it bends back should be straight up and down for and aft when in nuetral.
There is a basic formula for the left to right rotation adjustment at the coupler but it's never worked for me and I trial and error screw with it for a while rechecking it before I find where it works best.

If nothing else seems to fix it then you can drain the oil and remove the small inspection cover on the bottom and look up in there with flashlight to see if everything looks right including the small bolted on shift linkage pivot guide, shift rods and forks, synchro teeth and other visable synchro parts when in nuetral and when different gears are selected.

If you don't know what to look for thats possibly a waste of time.. you can collect the used gearbox oil and put it back in if it's low mileage clean and you don't want to change it yet.

You'll need a new paper gasket when reinstalling the bottom cover. It's about $4 and sometimes the aluminum cover is warped from the 8mm nylocks being overtightened. If thats happened the gasket and mating surface will not fit flush against each other and will leak so it will need a thicker than normal layer of thick gasket sealer to fill it in and seal it.
I don't use silicone gasket sealer on porsches but it will work there to fill in the gap from a warped cover if you let it dry overnight before refilling with gear oil.

As Fairman said, you have to pull the inspection plate. The fork on the plate lines up the selector. If its loose get a good cover as the threads have pulled out of the one removed.
The selector is suposed to line up the 2 sets of rails inside but you can do it with a screw driver. Now everything is out of gear..
Replace the cover with guide over the selector and follow previous instructions.
You need a new swivel in the tunnel as the threads are shot.
Bruce

Thank you! Will advise what I find out.